The Ullmann coupling reaction of aromatic halides is the most challenging C–C coupling reaction.Both MOF-based and MOF-deriffed types of catalysts haffe recently proffided useful nanocatalysts for a ffariety of react...The Ullmann coupling reaction of aromatic halides is the most challenging C–C coupling reaction.Both MOF-based and MOF-deriffed types of catalysts haffe recently proffided useful nanocatalysts for a ffariety of reactions,but they haffe rarely been compared.Herein,the Ullmann-type aryl iodide homocoupling is effciently catalyzed by gold and palladium nanoparticles(NPs)loaded on ZIF-8 before(ZIF-8-based nanocatalyst:M@ZIF-8)and after calcination(ZIF-8-deriffed catalyst:M@CN).The nanocatalysts M@ZIF-8(M=Pd,Au)are found to be more effcient than the catalysts M@CN.Pd@ZIF-8 exhibits better perform ances than those of Au@ZIF-8 for a series of aryl iodides,but in the case of 4-nitro-iodobenzene,deshy droiodination was obserffed besides the coupling product.Mechanisms are proposed and discussed for both Au(0)and Pd(0)nanocatalysts.展开更多
Enhancing the optical anisotropy of compounds is a pivotal pursuit with significant implications.In this study,we employed effective strategies by combining two high polarizability groups containing stereochemically a...Enhancing the optical anisotropy of compounds is a pivotal pursuit with significant implications.In this study,we employed effective strategies by combining two high polarizability groups containing stereochemically active lone pairs(SCALP),two novel ultraviolet(UV)birefringent materials:SbTeO_(3)Cl(STC)and SbTeO_(3)Br(STB)were synthesized successfully through hydrothermal reaction.Both compounds exhibit a honeycomb-like two-dimensional(2D)layer structure comprised of 6-membered rings(6-MRs)formed by[SbO_(3)X]^(4-)(where X=Cl,Br)seesaws and[TeO_(3)]^(2-)triangular pyramids.This superior 2D layered structure induces significant birefringence in both compounds,with values of 0.223@546 nm and 0.281@546 nm,respectively.Furthermore,the introduction of highly electronegative halogens(Cl^(-),Br^(-))succeeded in making the cutoff edges of both compounds fall in the UV region(325 nm and 340 nm,respectively).Detailed theoretical analyses elucidate that the substantial optical anisotropy arises from the synergistic interaction between the[SbO_(3)X]^(4-)(where X=Cl,Br)and[TeO_(3)]^(2-)groups.This study provides valuable insights into the discovery of function-driven,high-performance optical materials for future applications.展开更多
基金the China Scholarship Council of the People’s Republic of China(PhD grant to W.W.),the National Science Center of Poland under the program OPUS(E.C.and S.M.:2019/33/B/ST5/01495)the University of Bordeaux,the Centre National de la Recherche Scientifique(CNRS)and CIC biomaGUNE is gratefully acknowledged.
文摘The Ullmann coupling reaction of aromatic halides is the most challenging C–C coupling reaction.Both MOF-based and MOF-deriffed types of catalysts haffe recently proffided useful nanocatalysts for a ffariety of reactions,but they haffe rarely been compared.Herein,the Ullmann-type aryl iodide homocoupling is effciently catalyzed by gold and palladium nanoparticles(NPs)loaded on ZIF-8 before(ZIF-8-based nanocatalyst:M@ZIF-8)and after calcination(ZIF-8-deriffed catalyst:M@CN).The nanocatalysts M@ZIF-8(M=Pd,Au)are found to be more effcient than the catalysts M@CN.Pd@ZIF-8 exhibits better perform ances than those of Au@ZIF-8 for a series of aryl iodides,but in the case of 4-nitro-iodobenzene,deshy droiodination was obserffed besides the coupling product.Mechanisms are proposed and discussed for both Au(0)and Pd(0)nanocatalysts.
基金supported by the National Natural Science Foundation of China(Grant No.22122106,22071158,22375139,22305166)the Fundamental Research Funds from Sichuan University(2021 SCUNL101)the Natural Science Foundation of Sichuan Province(2023NSFC1066).
文摘Enhancing the optical anisotropy of compounds is a pivotal pursuit with significant implications.In this study,we employed effective strategies by combining two high polarizability groups containing stereochemically active lone pairs(SCALP),two novel ultraviolet(UV)birefringent materials:SbTeO_(3)Cl(STC)and SbTeO_(3)Br(STB)were synthesized successfully through hydrothermal reaction.Both compounds exhibit a honeycomb-like two-dimensional(2D)layer structure comprised of 6-membered rings(6-MRs)formed by[SbO_(3)X]^(4-)(where X=Cl,Br)seesaws and[TeO_(3)]^(2-)triangular pyramids.This superior 2D layered structure induces significant birefringence in both compounds,with values of 0.223@546 nm and 0.281@546 nm,respectively.Furthermore,the introduction of highly electronegative halogens(Cl^(-),Br^(-))succeeded in making the cutoff edges of both compounds fall in the UV region(325 nm and 340 nm,respectively).Detailed theoretical analyses elucidate that the substantial optical anisotropy arises from the synergistic interaction between the[SbO_(3)X]^(4-)(where X=Cl,Br)and[TeO_(3)]^(2-)groups.This study provides valuable insights into the discovery of function-driven,high-performance optical materials for future applications.
